Cardiac arrhythmias currently affect over 14 million and claim the lives of an estimated 450,000 people each year in the US. Two common treatments for arrhythmia patients are cardioversion and defibrillation. In these treatments, clinicians deliver high-energy electrical shocks to the heart to convert it to normal sinus rhythm. However, there is no guarantee that any given shock will work; if a given shock does not work, clinicians must make decisions, often in a matter of seconds, on what to do to increase the chance of success on the next shock. If the first shock fails, the current standard of care dictates that the only easily accessible option clinicians have is to increase the energy of the shock. However, this practice can cause unnecessarily pain for the patient without ensuring increased success. According to literature, less harmful but possibly equally effective alternatives, such as switching shock vectors or reducing transthoracic impedance, exist. Unfortunately, these alternatives are out of reach because there is no safe, standardized way to implement them quickly.
In particular, observed methods of decreasing transthoracic impedance in cardioversion settings have been observed to be unstandardized and crude. Physicians have been observed to use various mechanisms to apply pressure over desired external electrode patches such as using their fist, pushing down on patches with folded towels, or even using other non-related clinical implements such as urinal bottles. The effect of applying pressure over external adhesive electrode patches is to increase the quality of patch to skin contact, therein increasing adhesion and reducing the effective transthoracic impedance while delivering a defibrillator shock. It is clear that physicians acknowledge the utility of decreasing the transthoracic impedance before defibrillation, but the quality of the transthoracic impedance reduction is currently unknown as current standards do not provide quantitative or qualitative feedback on the amount of pressure exerted. Furthermore, current common practices contradict common resuscitation guidelines to clear the patient area and step away from the patient before delivering a defibrillator shock. In particular, the current unstandardized methods of impedance reduction have been observed to necessitate physicians to stay in close proximity to the patient throughout the duration of the shock, therein increasing the risk of accidental shock of the physician.
The field of this invention lies in the area of reducing transthoracic impedance through the application of standardized pressure, and the prior art contains a few objects of note. One method of reducing transthoracic impedance falls under the category of applying external pressure to the thoracic cavity. WO1992000716 A1 refers to an external cardiac massage device which applies rhythmic pressure to the sternum. Similarly, CA2066297 C refers to devices and methods for external chest compression which maintain a minimum residual pressure on the patient throughout the compression cycle. CA2117275 C and U.S. Pat. No. 5,891,062 refer to methods of active compression and decompression of the chest for CPR while using plunger-inspired patient body interfaces, while also utilizing a force gauge to monitor quality of CPR compressions. Furthermore, US20130060173 A1 refers to a method of providing CPR compressions to a patient which utilizes accelerometer data to determine the depth of compression.
Although the prior art shows mechanisms of applying rhythmic pressure to the sternum during resuscitation, there is currently no standardized method for the purposes of reducing transthoracic impedance when using external defibrillation adhesive electrode patches, and thus the intellectual property landscape is clear.